Doctor blade and control means therefor



Dec. l2` 1959 w. P. MILLER 2,915,421

DocToR BLADE AND CONTROL MEANS THEREFOR v Filed Nov. 14. 1956 3 Sheets-Sheet 1 IN V EN TOR.

. BY jimmy S7 wil/fam P. Mil/er Dec. l, 1959 w. P. MILLER 2,915,421

DOCTOR BLADE AND CONTROL MEANS THEREF'OR Filed Nav. 14, 1956 s sheets-sheet 2 Wil/iam P. Mil/er INVENTOR.

:s sheetssneet s Wil/iam P. Mil/er IN VEN TOR.

Dec. l, 1959 w. P. MILLER l DocToR BLADE AND coNTRoL MEANS 'mEREFoR Filed Nov. 14. 1956 TM Y N m Pw/Tel um .LA l

United States Patent O DOCTOR BLADE AND CONTROL MEANS '['IBEREFOR William P. Miller, Cincinnati, Ohio Application November 14, 1956, Serial No. 622,080

8 Claims. (Cl. 134-6) This invention comprises a novel and useful doctor blade and control means therefor, and more specically relates to a mechanism whereby a doctor blade may be applied to the surface of an industrial roller in a greatly improved manner.

The primary purpose of this invention is to provide a method and an apparatus for automatically cleaning the surfaces of industrial rollers and maintaining the same in a clean condition.

A further important object of the invention is to` provide an apparatus for applying a doctor blade directly upon the centerline of a roller and for maintaining the doctor blade against the surface of the roller by a thrust applied directly against the rear of the blade.

An additional object of the invention is to provide an apparatus whereby a doctor blade may be automatically applied to an industrial roller at a predetermined, adjustable and constant pressure.

A still further important object of the invention is to provide a method and apparatus for applying a doctor blade to the surface of an industrial roller whereby even wear of the cleaning edge of the blade and an automatic compensation for wear thereof is effected.

Yet another object of the invention is to provide a method and apparatus whereby the efficiency of performance and the length of useful service of a doctor blade may be greatly increased.

An additional important object of the invention is to provide a method and an apparatus whereby a predetermined, adjustable and constant resilient pressure is maintained upon a doctor blade for urging the same against the surface of an industrial roller.

Yet another object of the invention is to provide an electrically actuated mechanism for automatically maintaining a doctor blade against the surface of a roller with a predetermined, adjustable and constant pressure and with an automatic compensation for wear thereof.

These together with other objects and advantages which will become subsequently apparent reside in the detailsof construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure l is a front elevational view, parts being broken away to show certain internal details of the mechanism, and showing a mechanism for controlling the application of doctor blades to the surfaces of industrial rollers, certain concealed parts being shown in dotted lines therein;

Figure 2 is an enlarged detailed view taken in vertical transverse section substantially upon the plane indicated by the section line 2 2 of Figure l and showing the control means whereby the doctor blade is applied to a roller;

Figure 3 is a further detailed view in Vertical transverse section taken substantially upon the plane indicated by the section line 3 3 of Figure l and showing furtLer structural details of this invention;

Figure 4 is a still further detailed view taken upon an enlarged scale in vertical transverse section and substantially upon the plane indicated by the broken section line 4 4 of Figure l;

Figure 5 is a further detailed view taken in horizontal section upon an enlarged scale substantially upon the plane indicated by the section line 5 5 of Figure l;

Figure 6 is a perspective view of a doctor blade in accordance wtih this invention;

Figure 7 is an elevational view of a cover plate forming a part of the invention; and,

Figures 8 and 9 are perspective views of further elements forming a part of the invention.

Referring iirst to Figures 2 and 3 of the drawings, it will be seen that the surface of an industrial roller 10 is engaged by the forward edge of a doctor blade 12 along a radius of the roller as indicated at 14. By this arrangement, wear of the doctorblade by its rubbing contact with the surface of the industrial roller which is cleaned by the blade is uniform, and the blade, being fed forward and maintained in Contact with the surface of the roller at a constant pressure, as set forth hereinafter, is thus caused to wear evenly, resulting in a more effective operation of the doctor blade upon the roller and in an increased life of useful service of the doctor blade.

As will be further observed from Figures 2 and 3, a casing or housing 16 is provided in which is slidably and gnidably mounted the doctor blade l2 and in which is disposed `an operating mechanism for automatically cornpensating for wear of the doctor blade and for maintaining a constant resilient pressure of the doctor blade against a surface of the roller. Conveniently, the housing is disposed somewhat below the axis of the roller, so that the doctor blade is positioned at an incline to the horizontal plane, and whereby the housing 16 is provided with a slanting or inclined top wall 18, which also comprises a cover plate, although it will be understood that this particular position and arrangement is not essential for the purposes of this invention.

Referring next to Figure 6, it will be seen that the doctor blade comprises a rectangular shaped plate-like body, of any suitable material, and which at its rearward end has a downwardly inclined notched plate or plates 20 constituting a pressure bar for applying pressure to the rear end of the doctor blade. A flat strip 22 constituting a slide bar for the doctor blade is secured to the top surface of the doctor blade and to the pressure bar 29 as by means of fastening screws 24. The pressure bar or bars 2t) is provided with a suitable number of apertures 26 therethrough for a purposel to be subsequently set forth.

As will be best seen from Figures 2-4, the undersurface of the top Wall 1S is provided with a recess 30 which constitutes a guide for slidably receiving the slide bar 2 2 therein, while a slot 32 in the housing 16 also constitutes a guide means for the doctor blade. Thus, the doctor blade is guided for sliding movement while being maintained in a radial position with respect to the industrial roller lll.

Referring now in particular to Figures l and 2, it will be seen that there is provided an electric motor 34 of any suitable type and which is disposed in a suitable cornpartment within the housing for operating the actuating mechanism of the doctor blade. Through a suitable reduction gearing the motor drives the gear 36 which, in turn, operates through a gear 38 the shaft 40 which eX- tends longitudinally of the housing 16 and is journaled in suitable bearings therein. Secured to the shaft 40 are a plurality of operators 42 thereon, each of these operators as shown in Figure 9 consisting of a sleeve or hub portion 44 embracing and secured to the shaft 40,

and having a pair of parallel crank arms 46 projecting radially therefrom, these arms being apertured as at 48.

Pivoted to the crank arms 46 constituting the operators, as by a pin 50, is a pressure rod 52 apertured as at 54 for the reception of the above mentioned pin. At its forward end the pressure rod 52 is provided with an enlarged head 56, which as shown in Figure 2, screwthreadedly receives the end of a guide pin 58 slidably and loosely received in the apertures 26 of the pressure bars 20. A compression spring 60 is disposed about the member 58 and has its extremities abutting against the rear surface of the pressure bars 20 and the forward surface of the head 56.

As so far described, it will now be apparent that upon rocking movement of the shaft 40 in a counterclockwise direction as viewed in Figures 2 and 3, the pressure rods 52 will be moved forwardly, and thus will further compress the spring 60 and through this spring apply a resilient thrust to the pressure bars 20 to thereby yieldingly urge the doctor blade against the surface of the roller. It will be further seen that such rocking motion of the shaft 40 can be effected by suitable actuation of the electric motor 34 operatively connected thereto.

It will be observed that suitable partitions or reinforcing webs 62 may be provided in the housing 16 to strengthen the same, and furnish journals for the shaft 40 as well as supporting and guiding surfaces for the doctor blade 12 and its slide bar 22.

In order to render the operation of the motor and the mechanism connecting the same to the pressure bars n the doctor blade automatic, there is provided a microswitch 64, having a push-button 66 for actuating the same, whereby the microswitch is pressure responsive. One of the pressure rods 52 is provided with a laterally and forwardly extending finger 68, which as shown best in Figures 1 and 4, is adapted to engage the switch actuating element 66.

The arrangement is such that when wear upon the edge of the doctor blade permits the latter to move forwardly thereby reducing the pressure of the spring 60 and also carrying forwardly the switch 64 and its actuating member 66, the switch actuating member 66 is free to move outwardly from the switch 64 which is carried by the doctor blade through its pressure bar, thereby causing the switch to energize the electric motor, rotate the shaft 40 and cause the actuating rods thereon to compress the spring 60 and again restore the desired pressure to the pressure bars.

It will thus be apparent that there has been provided an automatic control mechanism for maintaining a predetermined and adjustable pressure upon the doctor blade, thereby compensating for wear and effecting e'icient operation of the doctor blade.v

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described,

and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A doctor blade assembly comprising a doctor blade, means supporting said doctor blade for engaging the surface of a roller to be serviced thereby in a position radial to the'axis of the roller, spring means operatively engaging the doctor blade for resiliently urging the same against the roller, a pressure rod for said spring means and operable to compress the same, an operator means controlling movement of each said pressure rod and including an electric motor, a pressure responsive switch mounted upon said doctor blade for controlling said motor, switch actuating means operatively associated with a pressure rod and with said switch to effect operation of said operator means for maintaining a predetermined constant force upon said spring means.

2. The method of maintaining a doctor blade in operative scraping contact with the surface of a roller to be treated thereby which comprises applying a doctor blade radially to the surface of a roller, applying a force to the rear of the doctor blade and in alignment therewith to resiliently press the doctor blade against a roller, maintaining said force at a predetermined pressure whereby to compensate for wear of the doctor blade.

3. The method of claim 2 including the step of employing a decrease in said predetermined pressure resulting from wear on the blade to effect a restoration of said force to said predetermined pressure.

4. The combination of claim 1 wherein said supporting means includes a guide for supporting and guiding the blade for sliding movement radially of the roller.

5. The combination of claim 1 wherein said doctor blade has a pressure bar secured thereto, said spring means engaging said pressure bar, retaining means on said pressure bar for positioning said spring means.

6. The combination of claim 1 wherein said operator means includes a shaft, operators on said shaft engaging said actuator bars, the latter having operative engagement with said spring means, said electric motor being connected to said shaft.

7. The combination of claim l wherein said switch actuating means includes a linger extending from one of said pressure rods for operation of said pressure responsive switch.

8. The combination of claim 1 wherein said operator means includes a shaft connected to said motor, cranks on said shaft, each pressure rod being operatively connected to one of said cranks.

References Cited in the file of this patent UNITED STATES PATENTS 328,413 Krutsch Oct. 13, 1885 429,381 Harvey June 3, 1890 1,704,853 Berry Mar. 12, 1929 2,474,052 Johnson June 2l, 1949 2,691,326 McArn Oct. 12, 1954 

1. A DOCTOR BLADE ASSEMBLY COMPRISING A DOCTOR BLADE, MEANS SUPPORTING SAID DOCTOR BLADE FOR ENGAGING THE SURFACE OF A ROLLER TO BE SERVICED THEREBY IN A POSITION RADIAL TO THE AXIS OF THE ROLLER, SPRING MEANS OPERATIVELY ENGAGING THE DOCTOR BLADE FOR RESILIENTLY URGING THE SAME AGAINST THE ROLLER, A PRESSURE ROD FOR SAID SPRING MEANS AND OPERABLE TO COMPRESS THE SAME, AN OPERATOR MEANS CONTROLLING MOVEMENT OF EACH SAID PRESSURE ROD AND INCLUDING AN ELECTRIC MOTOR, A PRESSURE REPONSIVE SWITCH MOUNTED UPON SAID DOCTOR BLADE FOR CONTROLLING SAID MOTOR, SWITCH ACTUATING MEANS OPERATIVELY ASSOCIATED WITH A PRESSURE ROD AND WITH SAID SWITCH TO EFFECT OPERATION OF SAID OPERATOR MEANS FOR MAINTAINING A PREDETERMINED CONSTANT FORCE UPON SAID SPRING MEANS.
 2. THE METHOD OF MAINTAINING ADOCTOR BLADE IN OPERATIVE SCRAPING CONTACT WITH THE SURFACE OF A ROLLER TO BE TREATED THEREBY WHCIH COMPRISES APPLYING A DOCTOR BLADE RADIALLY TO THE SURFACE OF A ROLLER, APPLYING A FORCE TO THE REAR OF THE DOCTOR BLADE AND IN ALIGNMENT THEREWITH TO RESILIENTLY PRESS THE DOCTOR BLADE AGAINST A ROLLER, MAINTAINING SAID FORCE AT A PREDETERMINED PRESSURE WHEREBY TO COMPENSATE FOR WEAR OF THE DOCTOR BLADE. 